From: Andi Kleen <andi@firstfloor.org>
To: Li Yang <leoli@freescale.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, gregkh@suse.de
Subject: Re: [RFC] char/mem: Honor O_SYNC over intelligent setting of uncached access
Date: Wed, 18 Nov 2009 11:41:01 +0100 [thread overview]
Message-ID: <873a4c5d4y.fsf@basil.nowhere.org> (raw)
In-Reply-To: <1258531548-5015-1-git-send-email-leoli@freescale.com> (Li Yang's message of "Wed, 18 Nov 2009 16:05:48 +0800")
Li Yang <leoli@freescale.com> writes:
D> The original code will automatially set the page non-cacheable if the mmap'ped
> address is not in kernel managed low memory.
>
> We already have O_SYNC flag to pass the cacheability settings. Therefore we should
> honor the case that O_SYNC is delibrately not used. For example, it is useful to the
> case that not all system memory is managed by Linux, and want to be mmaped cacheable.
>
> Not sure if there is anything out there depending on the previous behavior.
Very likely there is. That change seems rather dangerous.
If you wanted to do something like this you would need a long
deprecation period with printks and format warnings. But most likely
it's not worth it, what advantage does the change have?
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2009-11-18 10:40 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-18 8:05 [RFC] char/mem: Honor O_SYNC over intelligent setting of uncached access Li Yang
2009-11-18 10:41 ` Andi Kleen [this message]
2009-11-18 11:22 ` Li Yang
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